1. Field of the Invention
This invention relates to the medical arts and particularly to splinting devices including those orthopedic supports utilized during tissue healing and rehabilitation such as the healing of bones following fracture. Additional applications of the present invention include splinting devices for immobilization and support following soft tissue disorders, rheumatological joint disease and neurological conditions that result in muscle or tissue disease requiring support. Orthopedic rehabilitation usually occurs in successive phases from the acute phase immediately following injury or surgery; the intermediate phase of continued tissue healing where immobilization stabilized the injury for continued healing and the chronic phase where prolonged rehabilitation may be necessary. Support and protection of the injured tissues are conventionally provided by one or more of splinting materials available including plaster, premolded polymers and thermoplastic "custom" formable polymers.
For many years plaster casts provided the accepted mode of fracture fixation or immobilization of joints or other body tissue during healing. Plaster has now been replaced with a variety of synthetic materials, many of which are thermoforming materials which allow a more expeditious and accurate casting or immobilization of the affected portion of the body. Synthetic casting materials are now readily available in sheet stock and pre-forms which are cut to accommodate particular body parts or joints such as arms, wrists and hands as well as torso supports, shoe inserts cervical braces, back braces, foot supports, lower extremity diabetic foot care products, wheel chair inserts, cervical braces and total contact casting applications. It is now common that these splinting materials are made of a low temperature thermoplastic material, meaning that they may be custom formed in a plastic state at a comparatively low temperature however, when in the cooled state (ambient air/body temperature) they are sufficiently rigid to provide the support and protection to healing bones and tissue. If the splinting material is in sheet stock, it is cut in known manner to the approximate shape for application to the particular area of the body to be treated. Such low temperature thermoplastic materials are typically heated to temperatures in the vicinity of 160.degree. to 175.degree. F. in either a heated water bath or a hot air/conventional oven, at which temperature the material is formable on the body part to be splinted. The pliable, warmed splinting material is then fitted over the body part to be supported and is molded and trimmed to the final shape as the material cools and regains its rigid characteristic.
Splinting materials frequently introduce a level of discomfort to the wearer, either through buildup of moisture and/or heat in the affected region of the body. Thermoplastic splinting materials are usually available in perforated form to provide some relief to the associated discomfort. Another frequent discomfort or irritation comes from the development of pressure points where the bony prominences bear upon the formed splint. Splinting materials manufacturers offer various padding, either as supplements to the splinting materials or offer a padded thermoplastic splinting material. These padding materials are typically of wide-ranging construction including orthopedic felt, moleskin padding, various polymer foam materials, including several with adhesive backings which may be cut and directly applied to selected locations of the splint.
2. Description of the Prior Art
Splinting materials such as plaster and thermoplastic materials, when formed into splints/orthotics, are hard, uncomfortable and irritating to bony prominences which come into contact with the splint. Traditional methods to reduce pressure points are to spot pad the splint/orthotic with foam padding or gel-like padding or to push out the splint over the bony prominences to create an air pocket or cavity adjacent the prominence. Most foam padding bottoms out and becomes ineffective. Spot padding, even with such as cellular foam padding materials only reduces the pressure over the area padded, and not the entire splint/orthotic, permitting a "hot spot" of some continued discomfort or irritation. Many foam padding materials are open celled and therefore absorb water when the splint/orthotic is routinely washed. When using open celled foam materials, the splint/orthotic needs to be air dried before being reapplied to avoid skin irritation.
Spot padding, or the prepadding of the thermoplastic material with conventional padding materials prior to heating is difficult and time consuming. Air frequently gets trapped between the splinting material and the padding causing air pockets as the material is heated leading to premature separation or movement of the padding.
Prior art prepadded materials include such as Multiform Soft Splint Material from AliMed.RTM. Inc. which combines a layer of 1/16 inch Multiform.TM. low temperature thermoplastic material with AliPlast.TM. 4E, a closed cell, self-adhesive foam padding material.
Another padded splinting material is available under the name of Silon STS.RTM., a trademark of Bio Med Sciences, Inc. This material is a combination of layers of high temperature thermoplastic rigid sheet material and a silicone elastomer and is useful for custom molding for the treatment of scar tissue. The silicone sheet is known to reduce/control scar formation. The material, since it is a high temperature thermoplastic and would burn the skin on the prolonged contact during forming the splint directly on the affected body part, requires casting of a negative plaster mold and a positive mold form to form the splint or orthotic.
The following closed and open cell foam padding materials (available from Smith & Nephew Inc, Rehabilitative Division, the assignee of the present application) include a self-adhesive and have been used to spot pad or pre-pad low temperature thermoplastic splinting materials. Other competitive companies have similar types of padding materials. All of these conventional materials bottom-out easily and are prone to air pockets when preapplied to the low temperature thermoplastic material.
Low-Tack Polycushion.RTM. Padding Material PA0 Polycushion.RTM. Padding PA0 Kushionflex.RTM. Padding PA0 Rolyan.RTM. Foam Padding PA0 Quickstick.TM. Padding PA0 Plastozate.RTM. Foam Material with Self-adhesive Back PA0 Rolyan.RTM. Contour Foam PA0 Moleskin Rolls PA0 Moleskin Padding PA0 Orthopedic Felt
While there are self-adhesive paddings available for use with traditional splints or the thermoplastic type, none are sufficiently resistant to bottoming out. Smith & Nephew Rehabilitation Division offers examples of such materials including a cloth-covered Sorbothane.RTM. Padding and an open celled foam sold under the trademark PPT.